Medium for producing images



June 2, 1942. M. D. M INTOSH 2,285,122

MEDIUM FOR PRODUCING IMAGES Filed April 1, 1959 JuRFnce' can TING SEA/SI 7-1250 GEL/97' F'ILM WH/ 7-5 ENS/7'! zero GEL/Q77 FILM WHITE I CK" Co LOPEJD /o sass nvvE/vv-oe Name/cs- D. N? /NTO5H 14 TT'OPNE Y Patented June 2, 1942 MEDIUM FOR PRODUCING IMAGES- Mauricc D. McIntosh, Cleveland, Ohio, assignor to Louis S. Sanders, Cleveland, Ohio Application April 1, 1939, Serial No. 265,465

11 Claims.

The invention has for its main objects the pro-' duction without treatment by the half-tone proccss of visible representations characterized by iull tones of black or other non-=actinic color and white or other actinic color and tone, values of all gradations intermediate the full tones and adapted for camera copy suitable for direct revision of novel media for the execution of such visible representations; and the provision of novel modes of preparing said media.

Further important objects of my invention'are the production of copy suitable for direct use as photographic negatives which copy shall without treatment by the half-tone process comprise full tones of black and white or other selected nonactinic and actinic colors, and tone formations of the selected colors in all desired gradations intermediate the full tones; and the provision of media suitable for the preparation of such copy. Other objects of the invention will become clear as the description thereof proceeds.

In the drawing forming part of this specification:

Figure 1 is a partial perspective View showing one embodiment of my invention.

Figure 2 is a horizontal section of the medium shown in Figure 1.

Figure 3 is a partial plan view of the medium of Figure 1 showing the application of the developer thereto.

Figure 4 is a partial perspective view show ing a modification of my invention.

Figure 5 is a partial plan view showing the application of the developer to the medium of Figure 4.

Figure 6 is a partial perspective view of another form of my invention.

Figure 7 is a partial perspective view of the medium suitable for use as a photographic negative.

Figure 8 is a horizontal section of the photographic negative of Figure 7.

Referring to the first embodiment of my invention illustrated in Figures 1 and 2 of the drawings, upon which visible representations may be executed, it will be seen to comprise a medium having abase to of white paper stock, preferably hard sized white drawing board or paper. Upon the base I0 I apply a thin film ll of gelatin, albumen, casein, glue or the like, which serves as a vehicle for a sensitive" or chemically developable substance. The film may carry the sensitive" substance in colloidal suspension or it may be coated therewith. Whatever procedure is employed the film is said to be sensitized. In the instant embodiment of my invention the film ll carries a chemically developable 'substance which is black or some other non-actinic color such as red, brown, orange, or yellow.

' Many chemical compounds having this characproduction as line photo-engravings; the proteristic are available. I prefer to sensitize the film of gelatin by a colloidal suspension of black lead sulphide. This I accomplish by soaking 113 parts 'of dry purified gelatin for about one hour in 950 parts of water, preferably cold, add 11 parts of sodium chloride and then heat the solution until all the gelatinand salt are dissolved. Parts stated are by weight. Heating temperature should not exceed 140 F., although the temperature may be varied with variations in the amounts of ingredients and so long as decomposition of the gelatin is avoided.

To the gelatin solution I add a soluble sulfide, such as ammonium sulphide, and to the resulting mass I add a solution of a soluble lead compound such as lead acetate. Precipitation of black lead sulphide in colloidal suspension in the gelatin solution follows and this black gelatin solution with its colloidal suspension of lead sulphide is used to coat the base I0.

This fihn is then coated by avery thin transparent or translucent film I2 of a gum or resinous material which is soluble in or penetrable by the hereinafter described chemical developers for the sensitized film I I. Gum benzoin, ammoniac,

sandarac, galbanum, olibanum, mastic, copal and damar are satisfactory substances for film l2. -A mixture of gum benzoin and ammoniac as a spirit extract is very effective and may be prepared by adding 5 grams of gum benzoin and 5 grams of gum ammoniac to 400 milliliters of ethylene glycol monoethylether. The sensitized gelatin film is coated with the filtrate from this mixture on a whirler or roller coating machine.

My medium is thus prepared for the application of a coating l3 of a transparent or translucent varnish which is insoluble in and impenetrable by the developer referred to above. The coating I3 is printed upon the film l2 for which it has a greater afiinity than for a glutinous substance, and has a multiplicity of small spaced openings l4 through which the film I2 is exposed. These openings are shown greatly enlarged in the drawing.

Application of a surface coating l5 completes my medium. A surface coating comprising by weight parts of 20% gum mastic in ethyl alcohol, 100 parts of 20% gum dammar in ethyl alcohol and parts of water is satisfactory and may be applied by a whirler type coating machine. This coating dries dull, translucent and minutely porous, presents the proper tooth" for a satisfactory drawing surface and is penetrable by but insoluble in the developers for the sensitized gelatin coating. Nearly all of the spirit soluble natural and synthetic resins and gums may be used for this purpose.

Water soluble gums in combination with spirit soluble gums and resins may also be used. A solution containing by weight 50 parts of 20% cherry gum in water and 50 parts of 20% gum galbanum in ethyl alcohol is satisfactory and is prepared by heating the water solution of cherry gum to boiling, slowly adding the alcohol solution of gumlgalbanum and stirring vigorously. This coating also dries dull and porous so as to be penetrable by the developer. Water soluble substances such as gum arabic, gum tragacanth, soluble starch, dextrin, etc., may be substituted for the cherry gum and the water insoluble resins and gums mentioned above may be used in place of gum galbanum.

The surface coating which I prefer, however, is a solution of 25% egg or blood albumen in water which may be applied in any of the well known ways. After this coating has dried the medium is immersed for about one minute in a solution of 3% sorbitol in water at a temperature of approximately 190 F. Sorbitol is hexahydric alcohol represented by the symbol CGHB(OH) s. The medium is then dried. The coating is dull, transparent or translucent and penetrable by and insoluble in the developer.

By reason of the presence of the lead sulphide in the gelatin film the medium is black in color. Chemical development proceeds, therefore, by the production, by a bleaching process, of'white dots, lines, areas or other units depending upon the form of the openings l4. Bleaching may be effected by oxidation, or reduction, by dissolving or other chemical change. For the particular sensitizer used, namely, lead sulphide, I use as a developing or bleaching agent a 5% aqueous solution of hydrogen peroxide.

Upon application of this developer IS the black lead sulphide in the portions of the gelatin film accessible through the openings [4 in the varnish resist film I3 is immediately oxidized to white lead sulfate, thus producing a. plurality of white dots, lines or areas against a black background. By varying the time of reaction between the developer and the lead sulphide, solid white areas or areas consisting of formations of white and black may be produced. The entire gamut of tone values may thus be obtained.

Development of any particular unit or area may be terminated by blotting up the developer. If permitted to remain the developer diffuses through the gelatin film expanding the area bleached.

Dilute hydrochloric acid may be used in place of hydrogen peroxide in which event white lead chloride will be formed.

The medium with any desired image developed thereon in the manner described, is immediately available as camera copy for the direct production of line photo-engravings.

Manganese dioxide, iodine, precipitated black silver and cupric oxide as well asother substances may be substituted for the lead sulphide. The manganese dioxide, which is black, may be bleached by stannous chloride, sulfurous acid or titanium trichloride. This bleaching action oocurs through reduction.. Iodine, which is brown, may be bleached through reduction by soluble thiosulphates, soluble sulfites and stannous chloride. Black precipitated silver may be bleached through oxidation by mercuric chloride. When black cupric oxide is employed hydrochloric acid or ammonium chloride may be used as the developer. Bleaching in this instance occurs through dissolving,

Development of tone values with these substances is obtained by the same procedure employed with the lead sulphide.

The purpose of my invention is also secured by a medium of somewhat different composition. The base l0 of this medium is a sheet of paper having a black or other non-a'ctinic colored surface. Any of the non-actinic colored papers of commerce made with water insoluble coloring material'is suitable for this purpose, but a paper sheet of about two-ply weight and of high rag content is preferred. If desired, any good white paper the surface of which is colored by black waterproof India ink may be used as the base.

Upon the non-actinic colored surface of the base I apply a gelatin film H carrying in suschemically developable material of sufficient opacity to photographically obscure said surface.

, This material is capable of being rendered transparent or translucent by chemical development so that the underlying colored surface of the base becomes photographically visible.

White calcium carbonate is an example of such a material. A calcium carbonate colloid in a gelatin solution is obtained by dissolving a soluble carbonate such as sodium carbonate in a gelatin solution, which may be prepared in the manner hereinabove described. A solution of some calcium compound, e. g., calcium chloride, is then added causing a precipitation of colloidal calcium carbonate in the gelatin solution which serves as the sensitized film II. A sufiicient quantity of the film is applied so that. a white surface is obtained.

Upon film I I are applied in the order stated the coating ll. of gum or resinous material, the printed film l3 of varnish resist having the multiplicity of openings 14 and the surface coating I5 thus completing my medium.-

For the chemical development of my medium to produce dots, lines or areas I can use a dilute solution of almost any water soluble acid to decompose the calcium carbonate in film II. A dilute solution of hydrochloric acid is satisfactory. Upon application of such a developer I'l to the medium the portions of the opaque calcium carbonate accessible through the openings M in the varnish resist are immediately dissolved, thereby liberating carbon dioxide gas and leaving a slight residue of transparent calcium chloride. The decomposition of the calcium carbonate destroys its opacity so that the underlying colored surface of the base sheet ll) becomes visible through said decomposed portions as dots, lines or areas. By blotting up or otherwise inhibiting action of thedeveloper light tone values of black or other non-actinic color are obtained. Continued application of the developer causes it to diffuse through the gelatin film under the varnish resist producing decomposition of greater portions of the opaque calcium carbonate and resulting larger transparent areas of the gelatin film through which the colored surface of the base sheet is visible. In this manner full tones of actinic and non-actinic coland some organic acids such as acetic acid. Ex-

amples of such hydroxides are lead hydroxide, bismuth hydroxide and cadmium hydroxide.

By my invention I am enabled to adapt my last described medium for use as a photographic negative. To this end, I introduce a transparent water insoluble sheet l8, such as a sheet of cellulose acetate, into the composition of said medium, placing it between the base sheet l and the gelatin-calcium carbonate film H. A variety of transparent sheets are commercially available which can be'substituted for the cellulose acetate sheet. sidered medium, the transparent sheet l8, preferably about 0.005" in thickness, is mounted upon the base ill by means of a transparent stripping adhesive which, when dry, permits the transparent sheet to be stripped from the base sheet. The remaining elements of the medium, namely, the sensitized gelatin coating, gum film, printed varnish resist and surface coating are applied in that order upon the transparent sheet.

The appearance of my considered medium is the same as that of my last described medium and the mode of development of images thereon is the same. However, upon completion of an image on said medium the colored paper base I0 is stripped from the rest of the medium so that the transparent sheet 18 now becomes the base sheet. With the removal of the colored sheet ID the transparent dots, lines or areas in the gelatin film ll through which the color of said sheet Ill was heretofore visible will actually appear as transparent portions. The remaining parts of the gelatin film in which the calcium carbonate is not decomposed, is sufliciently opaque to prevent the passage of light. Hence, the remainder of the medium is suitable for direct use as a photographic negative.

The photographic negative may be obtained without the employment of the colored base sheet l0. In this aspect of my invention the cellulose acetate sheet I8 is utilized as the base sheet upon which are disposed in the order named the gelatin-calcium film II, the gum or resinous coating [2, the varnishresist print I3 having the multiplicity of openings [4 andthe surface coating l5.

The development of this medium proceeds in the manner described for the development of the first mentioned photographic negative. Moreover, while it is more. practicable in said first described medium from which a photographic negative is secured to employ a white or other actinic colored chemically developable substance, an actinic or a non-actinic colored chemically developable substance may be used with equal facility in the second mentioned photographic negative medium. For example, 'black cupric oxide may constitute the chemically developable substance carried by the gelatin and transparent units obtained by development with dilute hydrochlcric acid or a solution of ammonium chloride. Iodine, which is brown, may serve as the chemically developable substance and its development obtained by the applicationof soluble sulphites or soluble thiosulphates. Absolute opacity is not secured with iodine nor is it necessary. Photographic opacity is sufficient.

It will be apparent that numerous changes and variations in the media and processes disclosed may be made without departing from the spirit of my invention will be clear to those skilled in the art. It is intended, therefore, that all such changes and variations be comprehended within this invention which is to be limited only by the scope of the claims apperided hereto.

If desired, the gum or resinous film and/or the surface coating may be omitted in the production of media which will embody my invention.

I claim:

1. As an article of manufacture a medium for I the preparation of images suitable for usev as In production of the concamera copy comprising a base sheet having a surface of non-actinic color, a chemically developable substance, a thin film of material which allows passage of light, a coating of material which allows passage of light'and has a greater affinity for said film than for said-chemically developable substance, said coating having a multiplicity of spaced openings through which which allows passage of light, said film permitting access of developers for said chemically developable substance, said first mentioned coating being insoluble in and impenetrable by said developers. a

2. As an article of manufacture a medium for the preparation of images suitable for use as camera copy comprising a base sheet having a surface of non-actinic color, a chemically developable substance and a coating of material which allows passage of light, said coating having a multiplicity of spaced openings through which said chemically developable substance is accessible, said coating being insoluble in and impenetrable by the developers for said chemically developable substance.

3. As an article of manufacture a medium for the preparation of images suitable for use as camera copy comprising a base sheet, a gelatinous surface carrying a non-actinic colored chemically developable substance, a thin film of material which allows passage of light, a coating of material which allows passage of light and has a greater afiinity for said fihn than for said gelatinous surface, said coating having a multiplicity of spaced openings through which said chemically developable substance is accessible and a surface coating of dull material which allows passage of light, said film permitting access of developers for said chemically developable substance, said first mentioned coating being insoluble in and impenetrable by said developers and said surface coating being insoluble in and penetrable by said developers.

4. As an article of manufacture a'medium for the preparation of images suitable for use as camera copy comprising a base sheet, a gelatinous surface carrying a non-actinic colored chemically developable substance and a coating of material which allows passage of light, said coating being insoluble in and impenetrable by the developers for said chemically developable substance, said coating having a plurality of spaced openings through which said chemically developable substance is accessible.

5. As an article of manufacture a medium for the preparation of images suitable for use as camera copy comprising a base sheet, a gelatinous surface carrying black lead sulphide and a coating of material which allows passage of light, said coating being insoluble in and impenetrable by the developers for said lead sulphide, said coating having a plurality of spaced I openings through which said lead sulphide is accessible.

6. As an article of manufacture a medium for the preparation of images suitable for use as camera copy comprising a base sheet having a surface of non-actinic colgr, said base sheet bearing an actinic colored chemically developable substance, said substance being photographically opaque, a thin film of material which permits access of developers for said substance, a coating of material which allows passage of light, said coating being insoluble in and impenetrable by said developers, said chemically developable substance being accessible through a multiplicity of openings in said coating and a surface coating of dull material which allows passage of light, said surface coating being insoluble in and penetrable by said developers.

'7. As an article of manufacture a medium for the preparation of images suitable for use as camera copy comprising a base sheet having a surface of non-actinic color, said base sheet bearing an actinic colored chemically developable substance, said substance being photographically opaque and a coating of material which allows passage of light, said coating being insoluble in and impenetrable by the developers for said substance, said chemically developable substance being accessible through a multiplicity of openings in said coating.

8. As an article of manufacture a medium for camera copy comprising a base sheet having a surface of non-actinic color, said base sheet hearing a white insoluble photographically opaque carbonate, and a coating of material which al-- lows passage of light, said coating being insoluble in and impenetrable by the developers for said carbonate, said coating having a multiplicity of openings through which said carbonate is accessible.

9. As an article of manufacture a medium for the preparation of images suitable for use as camera copy comprising a base sheet having a surface of non-actinic color, said base sheet bearing a white insoluble photographically opaque hydroxide, and a coating of material which allows passage of light, said coating being insoluble in and impenetrable by the developers for said hydroxide said coating having a multiplicity of openings through which said hydroxide is accessible.

10. As an article of manufacture a medium for the preparationof images suitable for use as camera copy comprising a base sheet having a surface of non-actinic color, said base sheet bearing a sheet of material which allows passage of light removably secured upon said base sheet, an actinic colored photographically opaque chemically developable substance, and a coating of.

material which allows passage of light and is insoluble in and impenetrable by the developers for said substance, said coating havinga multiplicity of spaced openings.

11. A medium comprising a sheet of material which allows passage of light, a coating of photographically opaque chemically developable substance, and a covering of material which allows passage of light and is insoluble in and impenetrable by the devolpers for said substance, said covering having a plurality of spaced openings.

MAURICE D. MCINTOSH. 

